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Beginner

Site to SIte VPN through a NAT device

I, i am having some trouble running a site to site vpn between two 3725 routers running c3725-advsecurityk9-mz124-15T1 which i hope i can get some help with, i am probably missing something here. The VPN ran fine when both VPN routers were connected directly to the internet and had public IPs on the WAN interfaces, but i have had to move one of the firewalls inside onto a private IP. The setup is now as below

VPN router A(192.168.248.253)---Company internal network----Fortigate FW-----internet----(217.155.113.179)VPN router B

Now the fortigate FW is doing some address translations
- traffic from 192.168.248.253 to 217.155.113.179 has its source translated to 37.205.62.5
- traffic from 217.155.113.179 to 37.205.62.5 has its destination translated to 192.168.248.253
- The firewall rules allow any traffic between the 2 devices, no port lockdown enabled.

- The 37.205.62.5 address is used by nothing else.

I basically have a GRE tunnel between the two routers and i am trying to encrypt it.


Router A is showing the below

SERVER-RTR#show crypto map
Crypto Map "S2S_VPN" 10 ipsec-isakmp
Peer = 217.155.113.179
Extended IP access list 101
access-list 101 permit gre host 192.168.248.253 host 217.155.113.179
Current peer: 217.155.113.179
Security association lifetime: 4608000 kilobytes/3600 seconds
PFS (Y/N): N
Transform sets={
STRONG,
}
Interfaces using crypto map S2S_VPN:
FastEthernet0/1

SERVER-RTR#show crypto sessio
Crypto session current status

Interface: FastEthernet0/1
Session status: DOWN
Peer: 217.155.113.179 port 500
IPSEC FLOW: permit 47 host 192.168.248.253 host 217.155.113.179
Active SAs: 0, origin: crypto map

Interface: FastEthernet0/1
Session status: UP-IDLE
Peer: 217.155.113.179 port 4500
IKE SA: local 192.168.248.253/4500 remote 217.155.113.179/4500 Active
IKE SA: local 192.168.248.253/4500 remote 217.155.113.179/4500 Inactive
IKE SA: local 192.168.248.253/4500 remote 217.155.113.179/4500 Inactive

Router B is showing the below

BSU-RTR#show crypto map
Crypto Map "S2S_VPN" 10 ipsec-isakmp
Peer = 37.205.62.5
Extended IP access list 101
access-list 101 permit gre host 217.155.113.179 host 37.205.62.5
Current peer: 37.205.62.5
Security association lifetime: 4608000 kilobytes/3600 seconds
PFS (Y/N): N
Transform sets={
STRONG,
}
Interfaces using crypto map S2S_VPN:
FastEthernet0/1


BSU-RTR#show crypto sess
Crypto session current status

Interface: FastEthernet0/1
Session status: DOWN
Peer: 37.205.62.5 port 500
IPSEC FLOW: permit 47 host 217.155.113.179 host 37.205.62.5
Active SAs: 0, origin: crypto map

Interface: FastEthernet0/1
Session status: UP-IDLE
Peer: 37.205.62.5 port 4500
IKE SA: local 217.155.113.179/4500 remote 37.205.62.5/4500 Active
IKE SA: local 217.155.113.179/4500 remote 37.205.62.5/4500 Inactive
IKE SA: local 217.155.113.179/4500 remote 37.205.62.5/4500 Inactive

I can see the counters incrementing over the ACL on both routers so i know GRE traffic is interesting.

Here are some debugs too
--------------
Router A

debug crypto isakmp

*Mar 2 23:07:10.898: ISAKMP:(1024):purging node 940426884
*Mar 2 23:07:10.898: ISAKMP:(1024):purging node 1837874301
*Mar 2 23:07:10.898: ISAKMP:(1024):purging node -475409474
*Mar 2 23:07:20.794: ISAKMP (0:0): received packet from 217.155.113.179 dport 500 sport 500 Global (N) NEW SA
*Mar 2 23:07:20.794: ISAKMP: Created a peer struct for 217.155.113.179, peer port 500
*Mar 2 23:07:20.794: ISAKMP: New peer created peer = 0x64960C04 peer_handle = 0x80000F0E
*Mar 2 23:07:20.794: ISAKMP: Locking peer struct 0x64960C04, refcount 1 for crypto_isakmp_process_block
*Mar 2 23:07:20.794: ISAKMP: local port 500, remote port 500
*Mar 2 23:07:20.794: ISAKMP: Find a dup sa in the avl tree during calling isadb_insert sa = 6464D3F0
*Mar 2 23:07:20.794: ISAKMP:(0):Input = IKE_MESG_FROM_PEER, IKE_MM_EXCH
*Mar 2 23:07:20.794: ISAKMP:(0):Old State = IKE_READY New State = IKE_R_MM1

*Mar 2 23:07:20.794: ISAKMP:(0): processing SA payload. message ID = 0
*Mar 2 23:07:20.794: ISAKMP:(0): processing vendor id payload
*Mar 2 23:07:20.794: ISAKMP:(0): vendor ID seems Unity/DPD but major 69 mismatch
*Mar 2 23:07:20.798: ISAKMP (0:0): vendor ID is NAT-T RFC 3947
*Mar 2 23:07:20.798: ISAKMP:(0): processing vendor id payload
*Mar 2 23:07:20.798: ISAKMP:(0): vendor ID seems Unity/DPD but major 245 mismatch
*Mar 2 23:07:20.798: ISAKMP (0:0): vendor ID is NAT-T v7
*Mar 2 23:07:20.798: ISAKMP:(0): processing vendor id payload
*Mar 2 23:07:20.798: ISAKMP:(0): vendor ID seems Unity/DPD but major 157 mismatch
*Mar 2 23:07:20.798: ISAKMP:(0): vendor ID is NAT-T v3
*Mar 2 23:07:20.798: ISAKMP:(0): processing vendor id payload
*Mar 2 23:07:20.798: ISAKMP:(0): vendor ID seems Unity/DPD but major 123 mismatch
*Mar 2 23:07:20.798: ISAKMP:(0): vendor ID is NAT-T v2
*Mar 2 23:07:20.798: ISAKMP:(0):found peer pre-shared key matching 217.155.113.179
*Mar 2 23:07:20.798: ISAKMP:(0): local preshared key found
*Mar 2 23:07:20.798: ISAKMP : Scanning profiles for xauth ...
*Mar 2 23:07:20.798: ISAKMP:(0):Checking ISAKMP transform 1 against priority 1 policy
*Mar 2 23:07:20.798: ISAKMP: encryption DES-CBC
*Mar 2 23:07:20.798: ISAKMP: hash SHA
*Mar 2 23:07:20.798: ISAKMP: default group 1
*Mar 2 23:07:20.798: ISAKMP: auth pre-share
*Mar 2 23:07:20.798: ISAKMP: life type in seconds
*Mar 2 23:07:20.798: ISAKMP: life duration (VPI) of 0x0 0x1 0x51 0x80
*Mar 2 23:07:20.798: ISAKMP:(0):atts are acceptable. Next payload is 0
*Mar 2 23:07:20.798: ISAKMP:(0):Acceptable atts:actual life: 0
*Mar 2 23:07:20.798: ISAKMP:(0):Acceptable atts:life: 0
*Mar 2 23:07:20.798: ISAKMP:(0):Fill atts in sa vpi_length:4
*Mar 2 23:07:20.798: ISAKMP:(0):Fill atts in sa life_in_seconds:86400
*Mar 2 23:07:20.798: ISAKMP:(0):Returning Actual lifetime: 86400
*Mar 2 23:07:20.798: ISAKMP:(0)::Started lifetime timer: 86400.

*Mar 2 23:07:20.798: ISAKMP:(0): processing vendor id payload
*Mar 2 23:07:20.798: ISAKMP:(0): vendor ID seems Unity/DPD but major 69 mismatch
*Mar 2 23:07:20.798: ISAKMP (0:0): vendor ID is NAT-T RFC 3947
*Mar 2 23:07:20.798: ISAKMP:(0): processing vendor id payload
*Mar 2 23:07:20.798: ISAKMP:(0): vendor ID seems Unity/DPD but major 245 mismatch
*Mar 2 23:07:20.798: ISAKMP (0:0): vendor ID is NAT-T v7
*Mar 2 23:07:20.798: ISAKMP:(0): processing vendor id payload
*Mar 2 23:07:20.798: ISAKMP:(0): vendor ID seems Unity/DPD but major 157 mismatch
*Mar 2 23:07:20.798: ISAKMP:(0): vendor ID is NAT-T v3
*Mar 2 23:07:20.798: ISAKMP:(0): processing vendor id payload
*Mar 2 23:07:20.798: ISAKMP:(0): vendor ID seems Unity/DPD but major 123 mismatch
*Mar 2 23:07:20.798: ISAKMP:(0): vendor ID is NAT-T v2
*Mar 2 23:07:20.798: ISAKMP:(0):Input = IKE_MESG_INTERNAL, IKE_PROCESS_MAIN_MODE
*Mar 2 23:07:20.798: ISAKMP:(0):Old State = IKE_R_MM1 New State = IKE_R_MM1

*Mar 2 23:07:20.802: ISAKMP:(0): constructed NAT-T vendor-rfc3947 ID
*Mar 2 23:07:20.802: ISAKMP:(0): sending packet to 217.155.113.179 my_port 500 peer_port 500 (R) MM_SA_SETUP
*Mar 2 23:07:20.802: ISAKMP:(0):Sending an IKE IPv4 Packet.
*Mar 2 23:07:20.802: ISAKMP:(0):Input = IKE_MESG_INTERNAL, IKE_PROCESS_COMPLETE
*Mar 2 23:07:20.802: ISAKMP:(0):Old State = IKE_R_MM1 New State = IKE_R_MM2

*Mar 2 23:07:20.822: ISAKMP (0:0): received packet from 217.155.113.179 dport 500 sport 500 Global (R) MM_SA_SETUP
*Mar 2 23:07:20.822: ISAKMP:(0):Input = IKE_MESG_FROM_PEER, IKE_MM_EXCH
*Mar 2 23:07:20.822: ISAKMP:(0):Old State = IKE_R_MM2 New State = IKE_R_MM3

*Mar 2 23:07:20.822: ISAKMP:(0): processing KE payload. message ID = 0
*Mar 2 23:07:20.850: ISAKMP:(0): processing NONCE payload. message ID = 0
*Mar 2 23:07:20.854: ISAKMP:(0):found peer pre-shared key matching 217.155.113.179
*Mar 2 23:07:20.854: ISAKMP:(1027): processing vendor id payload
*Mar 2 23:07:20.854: ISAKMP:(1027): vendor ID is Unity
*Mar 2 23:07:20.854: ISAKMP:(1027): processing vendor id payload
*Mar 2 23:07:20.854: ISAKMP:(1027): vendor ID is DPD
*Mar 2 23:07:20.854: ISAKMP:(1027): processing vendor id payload
*Mar 2 23:07:20.854: ISAKMP:(1027): speaking to another IOS box!
*Mar 2 23:07:20.854: ISAKMP:received payload type 20
*Mar 2 23:07:20.854: ISAKMP (0:1027): NAT found, the node inside NAT
*Mar 2 23:07:20.854: ISAKMP:received payload type 20
*Mar 2 23:07:20.854: ISAKMP:(1027):Input = IKE_MESG_INTERNAL, IKE_PROCESS_MAIN_MODE
*Mar 2 23:07:20.854: ISAKMP:(1027):Old State = IKE_R_MM3 New State = IKE_R_MM3

*Mar 2 23:07:20.854: ISAKMP:(1027): sending packet to 217.155.113.179 my_port 500 peer_port 500 (R) MM_KEY_EXCH
*Mar 2 23:07:20.854: ISAKMP:(1027):Sending an IKE IPv4 Packet.
*Mar 2 23:07:20.858: ISAKMP:(1027):Input = IKE_MESG_INTERNAL, IKE_PROCESS_COMPLETE
*Mar 2 23:07:20.858: ISAKMP:(1027):Old State = IKE_R_MM3 New State = IKE_R_MM4

*Mar 2 23:07:20.898: ISAKMP:(1024):purging SA., sa=64D5723C, delme=64D5723C
*Mar 2 23:07:20.902: ISAKMP (0:1027): received packet from 217.155.113.179 dport 4500 sport 4500 Global (R) MM_KEY_EXCH
*Mar 2 23:07:20.902: ISAKMP:(1027):Input = IKE_MESG_FROM_PEER, IKE_MM_EXCH
*Mar 2 23:07:20.902: ISAKMP:(1027):Old State = IKE_R_MM4 New State = IKE_R_MM5

*Mar 2 23:07:20.902: ISAKMP:(1027): processing ID payload. message ID = 0
*Mar 2 23:07:20.902: ISAKMP (0:1027): ID payload
next-payload : 8
type : 1
address : 217.155.113.179
protocol : 17
port : 0
length : 12
*Mar 2 23:07:20.902: ISAKMP:(0):: peer matches *none* of the profiles
*Mar 2 23:07:20.906: ISAKMP:(1027): processing HASH payload. message ID = 0
*Mar 2 23:07:20.906: ISAKMP:(1027): processing NOTIFY INITIAL_CONTACT protocol 1
spi 0, message ID = 0, sa = 6464D3F0
*Mar 2 23:07:20.906: ISAKMP:(1027):SA authentication status:
authenticated
*Mar 2 23:07:20.906: ISAKMP:(1027):SA has been authenticated with 217.155.113.179
*Mar 2 23:07:20.906: ISAKMP:(1027):Detected port floating to port = 4500
*Mar 2 23:07:20.906: ISAKMP: Trying to find existing peer 192.168.248.253/217.155.113.179/4500/ and found existing peer 648EAD00 to reuse, free 64960C04
*Mar 2 23:07:20.906: ISAKMP: Unlocking peer struct 0x64960C04 Reuse existing peer, count 0
*Mar 2 23:07:20.906: ISAKMP: Deleting peer node by peer_reap for 217.155.113.179: 64960C04
*Mar 2 23:07:20.906: ISAKMP: Locking peer struct 0x648EAD00, refcount 2 for Reuse existing peer
*Mar 2 23:07:20.906: ISAKMP:(1027):SA authentication status:
authenticated
*Mar 2 23:07:20.906: ISAKMP:(1027): Process initial contact,
bring down existing phase 1 and 2 SA's with local 192.168.248.253 remote 217.155.113.179 remote port 4500
*Mar 2 23:07:20.906: ISAKMP:(1026):received initial contact, deleting SA
*Mar 2 23:07:20.906: ISAKMP:(1026):peer does not do paranoid keepalives.

*Mar 2 23:07:20.906: ISAKMP:(1026):deleting SA reason "Receive initial contact" state (R) QM_IDLE (peer 217.155.113.179)
*Mar 2 23:07:20.906: ISAKMP:(0):Can't decrement IKE Call Admission Control stat incoming_active since it's already 0.
*Mar 2 23:07:20.906: ISAKMP:(1027):Setting UDP ENC peer struct 0x0 sa= 0x6464D3F0
*Mar 2 23:07:20.906: ISAKMP:(1027):Input = IKE_MESG_INTERNAL, IKE_PROCESS_MAIN_MODE
*Mar 2 23:07:20.906: ISAKMP:(1027):Old State = IKE_R_MM5 New State = IKE_R_MM5

*Mar 2 23:07:20.910: ISAKMP: set new node -98987637 to QM_IDLE
*Mar 2 23:07:20.910: ISAKMP:(1026): sending packet to 217.155.113.179 my_port 4500 peer_port 4500 (R) QM_IDLE
*Mar 2 23:07:20.910: ISAKMP:(1026):Sending an IKE IPv4 Packet.
*Mar 2 23:07:20.910: ISAKMP:(1026):purging node -98987637
*Mar 2 23:07:20.910: ISAKMP:(1026):Input = IKE_MESG_INTERNAL, IKE_PHASE1_DEL
*Mar 2 23:07:20.910: ISAKMP:(1026):Old State = IKE_P1_COMPLETE New State = IKE_DEST_SA

*Mar 2 23:07:20.910: ISAKMP:(1027):SA is doing pre-shared key authentication using id type ID_IPV4_ADDR
*Mar 2 23:07:20.910: ISAKMP (0:1027): ID payload
next-payload : 8
type : 1
address : 192.168.248.253
protocol : 17
port : 0
length : 12
*Mar 2 23:07:20.910: ISAKMP:(1027):Total payload length: 12
*Mar 2 23:07:20.914: ISAKMP:(1027): sending packet to 217.155.113.179 my_port 4500 peer_port 4500 (R) MM_KEY_EXCH
*Mar 2 23:07:20.914: ISAKMP:(1027):Sending an IKE IPv4 Packet.
*Mar 2 23:07:20.914: ISAKMP:(1027):Input = IKE_MESG_INTERNAL, IKE_PROCESS_COMPLETE
*Mar 2 23:07:20.914: ISAKMP:(1027):Old State = IKE_R_MM5 New State = IKE_P1_COMPLETE

*Mar 2 23:07:20.914: ISAKMP:(1026):deleting SA reason "Receive initial contact" state (R) QM_IDLE (peer 217.155.113.179)
*Mar 2 23:07:20.914: ISAKMP: Unlocking peer struct 0x648EAD00 for isadb_mark_sa_deleted(), count 1
*Mar 2 23:07:20.914: ISAKMP:(1026):deleting node 334747020 error FALSE reason "IKE deleted"
*Mar 2 23:07:20.914: ISAKMP:(1026):deleting node -1580729900 error FALSE reason "IKE deleted"
*Mar 2 23:07:20.914: ISAKMP:(1026):deleting node -893929227 error FALSE reason "IKE deleted"
*Mar 2 23:07:20.914: ISAKMP:(1026):Input = IKE_MESG_FROM_PEER, IKE_MM_EXCH
*Mar 2 23:07:20.914: ISAKMP:(1026):Old State = IKE_DEST_SA New State = IKE_DEST_SA

*Mar 2 23:07:20.914: ISAKMP:(1027):Input = IKE_MESG_INTERNAL, IKE_PHASE1_COMPLETE
*Mar 2 23:07:20.914: ISAKMP:(1027):Old State = IKE_P1_COMPLETE New State = IKE_P1_COMPLETE

*Mar 2 23:07:20.930: ISAKMP (0:1026): received packet from 217.155.113.179 dport 4500 sport 4500 Global (R) MM_NO_STATE
*Mar 2 23:07:20.934: ISAKMP (0:1027): received packet from 217.155.113.179 dport 4500 sport 4500 Global (R) QM_IDLE
*Mar 2 23:07:20.934: ISAKMP: set new node 1860263019 to QM_IDLE
*Mar 2 23:07:20.934: ISAKMP:(1027): processing HASH payload. message ID = 1860263019
*Mar 2 23:07:20.934: ISAKMP:(1027): processing SA payload. message ID = 1860263019
*Mar 2 23:07:20.934: ISAKMP:(1027):Checking IPSec proposal 1
*Mar 2 23:07:20.934: ISAKMP: transform 1, ESP_AES
*Mar 2 23:07:20.934: ISAKMP: attributes in transform:
*Mar 2 23:07:20.934: ISAKMP: encaps is 3 (Tunnel-UDP)
*Mar 2 23:07:20.934: ISAKMP: SA life type in seconds
*Mar 2 23:07:20.934: ISAKMP: SA life duration (basic) of 3600
*Mar 2 23:07:20.934: ISAKMP: SA life type in kilobytes
*Mar 2 23:07:20.934: ISAKMP: SA life duration (VPI) of 0x0 0x46 0x50 0x0
*Mar 2 23:07:20.934: ISAKMP: key length is 128
*Mar 2 23:07:20.934: ISAKMP:(1027):atts are acceptable.
*Mar 2 23:07:20.934: ISAKMP:(1027): IPSec policy invalidated proposal with error 32
*Mar 2 23:07:20.934: ISAKMP:(1027): phase 2 SA policy not acceptable! (local 192.168.248.253 remote 217.155.113.179)
*Mar 2 23:07:20.938: ISAKMP: set new node 1961554007 to QM_IDLE
*Mar 2 23:07:20.938: ISAKMP:(1027):Sending NOTIFY PROPOSAL_NOT_CHOSEN protocol 3
spi 1688526152, message ID = 1961554007
*Mar 2 23:07:20.938: ISAKMP:(1027): sending packet to 217.155.113.179 my_port 4500 peer_port 4500 (R) QM_IDLE
*Mar 2 23:07:20.938: ISAKMP:(1027):Sending an IKE IPv4 Packet.
*Mar 2 23:07:20.938: ISAKMP:(1027):purging node 1961554007
*Mar 2 23:07:20.938: ISAKMP:(1027):deleting node 1860263019 error TRUE reason "QM rejected"
*Mar 2 23:07:20.938: ISAKMP:(1027):Node 1860263019, Input = IKE_MESG_FROM_PEER, IKE_QM_EXCH
*Mar 2 23:07:20.938: ISAKMP:(1027):Old State = IKE_QM_READY New State = IKE_QM_READY
*Mar 2 23:07:24.510: ISAKMP: set new node 0 to QM_IDLE
*Mar 2 23:07:24.510: SA has outstanding requests (local 100.100.213.56 port 4500, remote 100.100.213.84 port 4500)
*Mar 2 23:07:24.510: ISAKMP:(1027): sitting IDLE. Starting QM immediately (QM_IDLE )
*Mar 2 23:07:24.510: ISAKMP:(1027):beginning Quick Mode exchange, M-ID of 670698820
*Mar 2 23:07:24.510: ISAKMP:(1027):QM Initiator gets spi
*Mar 2 23:07:24.510: ISAKMP:(1027): sending packet to 217.155.113.179 my_port 4500 peer_port 4500 (R) QM_IDLE
*Mar 2 23:07:24.510: ISAKMP:(1027):Sending an IKE IPv4 Packet.
*Mar 2 23:07:24.514: ISAKMP:(1027):Node 670698820, Input = IKE_MESG_INTERNAL, IKE_INIT_QM
*Mar 2 23:07:24.514: ISAKMP:(1027):Old State = IKE_QM_READY New State = IKE_QM_I_QM1
*Mar 2 23:07:24.530: ISAKMP (0:1027): received packet from 217.155.113.179 dport 4500 sport 4500 Global (R) QM_IDLE
*Mar 2 23:07:24.534: ISAKMP: set new node 1318257670 to QM_IDLE
*Mar 2 23:07:24.534: ISAKMP:(1027): processing HASH payload. message ID = 1318257670
*Mar 2 23:07:24.534: ISAKMP:(1027): processing NOTIFY PROPOSAL_NOT_CHOSEN protocol 3
spi 3268378219, message ID = 1318257670, sa = 6464D3F0
*Mar 2 23:07:24.534: ISAKMP:(1027): deleting spi 3268378219 message ID = 670698820
*Mar 2 23:07:24.534: ISAKMP:(1027):deleting node 670698820 error TRUE reason "Delete Larval"
*Mar 2 23:07:24.534: ISAKMP:(1027):deleting node 1318257670 error FALSE reason "Informational (in) state 1"
*Mar 2 23:07:24.534: ISAKMP:(1027):Input = IKE_MESG_FROM_PEER, IKE_INFO_NOTIFY
*Mar 2 23:07:24.534: ISAKMP:(1027):Old State = IKE_P1_COMPLETE New State = IKE_P1_COMPLETE

*Mar 2 23:07:40.898: ISAKMP:(1025):purging node -238086324
*Mar 2 23:07:40.898: ISAKMP:(1025):purging node -1899972726
*Mar 2 23:07:40.898: ISAKMP:(1025):purging node -321906720

Router B
----------
debug crypto isakmp

1d23h: ISAKMP:(0): SA request profile is (NULL)
1d23h: ISAKMP: Created a peer struct for 37.205.62.5, peer port 500
1d23h: ISAKMP: New peer created peer = 0x652C3B54 peer_handle = 0x80000D8C
1d23h: ISAKMP: Locking peer struct 0x652C3B54, refcount 1 for isakmp_initiator
1d23h: ISAKMP: local port 500, remote port 500
1d23h: ISAKMP: set new node 0 to QM_IDLE
1d23h: ISAKMP: Find a dup sa in the avl tree during calling isadb_insert sa = 652CBDC4
1d23h: ISAKMP:(0):Can not start Aggressive mode, trying Main mode.
1d23h: ISAKMP:(0):found peer pre-shared key matching 37.205.62.5
1d23h: ISAKMP:(0): constructed NAT-T vendor-rfc3947 ID
1d23h: ISAKMP:(0): constructed NAT-T vendor-07 ID
1d23h: ISAKMP:(0): constructed NAT-T vendor-03 ID
1d23h: ISAKMP:(0): constructed NAT-T vendor-02 ID
1d23h: ISAKMP:(0):Input = IKE_MESG_FROM_IPSEC, IKE_SA_REQ_MM
1d23h: ISAKMP:(0):Old State = IKE_READY New State = IKE_I_MM1

1d23h: ISAKMP:(0): beginning Main Mode exchange
1d23h: ISAKMP:(0): sending packet to 37.205.62.5 my_port 500 peer_port 500 (I) MM_NO_STATE
1d23h: ISAKMP:(0):Sending an IKE IPv4 Packet.
1d23h: ISAKMP (0:0): received packet from 37.205.62.5 dport 500 sport 500 Global (I) MM_NO_STATE
1d23h: ISAKMP:(0):Input = IKE_MESG_FROM_PEER, IKE_MM_EXCH
1d23h: ISAKMP:(0):Old State = IKE_I_MM1 New State = IKE_I_MM2

1d23h: ISAKMP:(0): processing SA payload. message ID = 0
1d23h: ISAKMP:(0): processing vendor id payload
1d23h: ISAKMP:(0): vendor ID seems Unity/DPD but major 69 mismatch
1d23h: ISAKMP (0:0): vendor ID is NAT-T RFC 3947
1d23h: ISAKMP:(0):found peer pre-shared key matching 37.205.62.5
1d23h: ISAKMP:(0): local preshared key found
1d23h: ISAKMP : Scanning profiles for xauth ...
1d23h: ISAKMP:(0):Checking ISAKMP transform 1 against priority 1 policy
1d23h: ISAKMP: encryption DES-CBC
1d23h: ISAKMP: hash SHA
1d23h: ISAKMP: default group 1
1d23h: ISAKMP: auth pre-share
1d23h: ISAKMP: life type in seconds
1d23h: ISAKMP: life duration (VPI) of 0x0 0x1 0x51 0x80
1d23h: ISAKMP:(0):atts are acceptable. Next payload is 0
1d23h: ISAKMP:(0):Acceptable atts:actual life: 0
1d23h: ISAKMP:(0):Acceptable atts:life: 0
1d23h: ISAKMP:(0):Fill atts in sa vpi_length:4
1d23h: ISAKMP:(0):Fill atts in sa life_in_seconds:86400
1d23h: ISAKMP:(0):Returning Actual lifetime: 86400
1d23h: ISAKMP:(0)::Started lifetime timer: 86400.

1d23h: ISAKMP:(0): processing vendor id payload
1d23h: ISAKMP:(0): vendor ID seems Unity/DPD but major 69 mismatch
1d23h: ISAKMP (0:0): vendor ID is NAT-T RFC 3947
1d23h: ISAKMP:(0):Input = IKE_MESG_INTERNAL, IKE_PROCESS_MAIN_MODE
1d23h: ISAKMP:(0):Old State = IKE_I_MM2 New State = IKE_I_MM2

1d23h: ISAKMP:(0): sending packet to 37.205.62.5 my_port 500 peer_port 500 (I) MM_SA_SETUP
1d23h: ISAKMP:(0):Sending an IKE IPv4 Packet.
1d23h: ISAKMP:(0):Input = IKE_MESG_INTERNAL, IKE_PROCESS_COMPLETE
1d23h: ISAKMP:(0):Old State = IKE_I_MM2 New State = IKE_I_MM3

1d23h: ISAKMP (0:0): received packet from 37.205.62.5 dport 500 sport 500 Global (I) MM_SA_SETUP
1d23h: ISAKMP:(0):Input = IKE_MESG_FROM_PEER, IKE_MM_EXCH
1d23h: ISAKMP:(0):Old State = IKE_I_MM3 New State = IKE_I_MM4

1d23h: ISAKMP:(0): processing KE payload. message ID = 0
1d23h: ISAKMP:(0): processing NONCE payload. message ID = 0
1d23h: ISAKMP:(0):found peer pre-shared key matching 37.205.62.5
1d23h: ISAKMP:(1034): processing vendor id payload
1d23h: ISAKMP:(1034): vendor ID is Unity
1d23h: ISAKMP:(1034): processing vendor id payload
1d23h: ISAKMP:(1034): vendor ID is DPD
1d23h: ISAKMP:(1034): processing vendor id payload
1d23h: ISAKMP:(1034): speaking to another IOS box!
1d23h: ISAKMP:received payload type 20
1d23h: ISAKMP:received payload type 20
1d23h: ISAKMP (0:1034): NAT found, the node outside NAT
1d23h: ISAKMP:(1034):Input = IKE_MESG_INTERNAL, IKE_PROCESS_MAIN_MODE
1d23h: ISAKMP:(1034):Old State = IKE_I_MM4 New State = IKE_I_MM4

1d23h: ISAKMP:(1034):Send initial contact
1d23h: ISAKMP:(1034):SA is doing pre-shared key authentication using id type ID_IPV4_ADDR
1d23h: ISAKMP (0:1034): ID payload
next-payload : 8
type : 1
address : 217.155.113.179
protocol : 17
port : 0
length : 12
1d23h: ISAKMP:(1034):Total payload length: 12
1d23h: ISAKMP:(1034): sending packet to 37.205.62.5 my_port 4500 peer_port 4500 (I) MM_KEY_EXCH
1d23h: ISAKMP:(1034):Sending an IKE IPv4 Packet.
1d23h: ISAKMP:(1034):Input = IKE_MESG_INTERNAL, IKE_PROCESS_COMPLETE
1d23h: ISAKMP:(1034):Old State = IKE_I_MM4 New State = IKE_I_MM5

1d23h: ISAKMP:(1031):purging SA., sa=652D60C8, delme=652D60C8
1d23h: ISAKMP (0:1033): received packet from 37.205.62.5 dport 4500 sport 4500 Global (I) QM_IDLE
1d23h: ISAKMP: set new node 33481563 to QM_IDLE
1d23h: ISAKMP:(1033): processing HASH payload. message ID = 33481563
1d23h: ISAKMP:received payload type 18
1d23h: ISAKMP:(1033):Processing delete with reason payload
1d23h: ISAKMP:(1033):delete doi = 1
1d23h: ISAKMP:(1033):delete protocol id = 1
1d23h: ISAKMP:(1033):delete spi_size = 16
1d23h: ISAKMP:(1033):delete num spis = 1
1d23h: ISAKMP:(1033):delete_reason = 11
1d23h: ISAKMP:(1033): processing DELETE_WITH_REASON payload, message ID = 33481563, reason: Unknown delete reason!
1d23h: ISAKMP:(1033):peer does not do paranoid keepalives.

1d23h: ISAKMP:(1033):deleting SA reason "Receive initial contact" state (I) QM_IDLE (peer 37.205.62.5)
1d23h: ISAKMP:(1033):deleting node 33481563 error FALSE reason "Informational (in) state 1"
1d23h: ISAKMP: set new node 1618266182 to QM_IDLE
1d23h: ISAKMP:(1033): sending packet to 37.205.62.5 my_port 4500 peer_port 4500 (I) QM_IDLE
1d23h: ISAKMP:(1033):Sending an IKE IPv4 Packet.
1d23h: ISAKMP:(1033):purging node 1618266182
1d23h: ISAKMP:(1033):Input = IKE_MESG_INTERNAL, IKE_PHASE1_DEL
1d23h: ISAKMP:(1033):Old State = IKE_P1_COMPLETE New State = IKE_DEST_SA

1d23h: ISAKMP (0:1034): received packet from 37.205.62.5 dport 4500 sport 4500 Global (I) MM_KEY_EXCH
1d23h: ISAKMP:(1034): processing ID payload. message ID = 0
1d23h: ISAKMP (0:1034): ID payload
next-payload : 8
type : 1
address : 192.168.248.253
protocol : 17
port : 0
length : 12
1d23h: ISAKMP:(0):: peer matches *none* of the profiles
1d23h: ISAKMP:(1034): processing HASH payload. message ID = 0
1d23h: ISAKMP:(1034):SA authentication status:
authenticated
1d23h: ISAKMP:(1034):SA has been authenticated with 37.205.62.5
1d23h: ISAKMP: Trying to insert a peer 217.155.113.179/37.205.62.5/4500/, and found existing one 643BCA10 to reuse, free 652C3B54
1d23h: ISAKMP: Unlocking peer struct 0x652C3B54 Reuse existing peer, count 0
1d23h: ISAKMP: Deleting peer node by peer_reap for 37.205.62.5: 652C3B54
1d23h: ISAKMP: Locking peer struct 0x643BCA10, refcount 2 for Reuse existing peer
1d23h: ISAKMP:(1034):Input = IKE_MESG_FROM_PEER, IKE_MM_EXCH
1d23h: ISAKMP:(1034):Old State = IKE_I_MM5 New State = IKE_I_MM6

1d23h: ISAKMP:(1033):deleting SA reason "Receive initial contact" state (I) QM_IDLE (peer 37.205.62.5)
1d23h: ISAKMP:(0):Can't decrement IKE Call Admission Control stat outgoing_active since it's already 0.
1d23h: ISAKMP: Unlocking peer struct 0x643BCA10 for isadb_mark_sa_deleted(), count 1
1d23h: ISAKMP:(1033):deleting node 1267924911 error FALSE reason "IKE deleted"
1d23h: ISAKMP:(1033):deleting node 1074093103 error FALSE reason "IKE deleted"
1d23h: ISAKMP:(1033):deleting node -183194519 error FALSE reason "IKE deleted"
1d23h: ISAKMP:(1033):deleting node 33481563 error FALSE reason "IKE deleted"
1d23h: ISAKMP:(1033):Input = IKE_MESG_FROM_PEER, IKE_MM_EXCH
1d23h: ISAKMP:(1033):Old State = IKE_DEST_SA New State = IKE_DEST_SA

1d23h: ISAKMP:(1034):Input = IKE_MESG_INTERNAL, IKE_PROCESS_MAIN_MODE
1d23h: ISAKMP:(1034):Old State = IKE_I_MM6 New State = IKE_I_MM6

1d23h: ISAKMP:(1034):Input = IKE_MESG_INTERNAL, IKE_PROCESS_COMPLETE
1d23h: ISAKMP:(1034):Old State = IKE_I_MM6 New State = IKE_P1_COMPLETE

1d23h: ISAKMP:(1034):beginning Quick Mode exchange, M-ID of 1297417008
1d23h: ISAKMP:(1034):QM Initiator gets spi
1d23h: ISAKMP:(1034): sending packet to 37.205.62.5 my_port 4500 peer_port 4500 (I) QM_IDLE
1d23h: ISAKMP:(1034):Sending an IKE IPv4 Packet.
1d23h: ISAKMP:(1034):Node 1297417008, Input = IKE_MESG_INTERNAL, IKE_INIT_QM
1d23h: ISAKMP:(1034):Old State = IKE_QM_READY New State = IKE_QM_I_QM1
1d23h: ISAKMP:(1034):Input = IKE_MESG_INTERNAL, IKE_PHASE1_COMPLETE
1d23h: ISAKMP:(1034):Old State = IKE_P1_COMPLETE New State = IKE_P1_COMPLETE

1d23h: ISAKMP (0:1034): received packet from 37.205.62.5 dport 4500 sport 4500 Global (I) QM_IDLE
1d23h: ISAKMP: set new node -874376893 to QM_IDLE
1d23h: ISAKMP:(1034): processing HASH payload. message ID = -874376893
1d23h: ISAKMP:(1034): processing NOTIFY PROPOSAL_NOT_CHOSEN protocol 3
spi 56853244, message ID = -874376893, sa = 652CBDC4
1d23h: ISAKMP:(1034): deleting spi 56853244 message ID = 1297417008
1d23h: ISAKMP:(1034):deleting node 1297417008 error TRUE reason "Delete Larval"
1d23h: ISAKMP:(1034):deleting node -874376893 error FALSE reason "Informational (in) state 1"
1d23h: ISAKMP:(1034):Input = IKE_MESG_FROM_PEER, IKE_INFO_NOTIFY
1d23h: ISAKMP:(1034):Old State = IKE_P1_COMPLETE New State = IKE_P1_COMPLETE

1d23h: ISAKMP (0:1034): received packet from 37.205.62.5 dport 4500 sport 4500 Global (I) QM_IDLE
1d23h: ISAKMP: set new node 439453045 to QM_IDLE
1d23h: ISAKMP:(1034): processing HASH payload. message ID = 439453045
1d23h: ISAKMP:(1034): processing SA payload. message ID = 439453045
1d23h: ISAKMP:(1034):Checking IPSec proposal 1
1d23h: ISAKMP: transform 1, ESP_AES
1d23h: ISAKMP: attributes in transform:
1d23h: ISAKMP: encaps is 3 (Tunnel-UDP)
1d23h: ISAKMP: SA life type in seconds
1d23h: ISAKMP: SA life duration (basic) of 3600
1d23h: ISAKMP: SA life type in kilobytes
1d23h: ISAKMP: SA life duration (VPI) of 0x0 0x46 0x50 0x0
1d23h: ISAKMP: key length is 128
1d23h: ISAKMP:(1034):atts are acceptable.
1d23h: ISAKMP:(1034): IPSec policy invalidated proposal with error 32
1d23h: ISAKMP:(1034): phase 2 SA policy not acceptable! (local 217.155.113.179 remote 37.205.62.5)
1d23h: ISAKMP: set new node 1494356901 to QM_IDLE
1d23h: ISAKMP:(1034):Sending NOTIFY PROPOSAL_NOT_CHOSEN protocol 3
spi 1687353736, message ID = 1494356901
1d23h: ISAKMP:(1034): sending packet to 37.205.62.5 my_port 4500 peer_port 4500 (I) QM_IDLE
1d23h: ISAKMP:(1034):Sending an IKE IPv4 Packet.
1d23h: ISAKMP:(1034):purging node 1494356901
1d23h: ISAKMP:(1034):deleting node 439453045 error TRUE reason "QM rejected"
1d23h: ISAKMP:(1034):Node 439453045, Input = IKE_MESG_FROM_PEER, IKE_QM_EXCH
1d23h: ISAKMP:(1034):Old State = IKE_QM_READY New State = IKE_QM_READY
1d23h: ISAKMP:(1032):purging node 1513722556
1d23h: ISAKMP:(1032):purging node -643121396
1d23h: ISAKMP:(1032):purging node 1350014243
1d23h: ISAKMP:(1032):purging node 83247347

1 ACCEPTED SOLUTION

Accepted Solutions
Highlighted

Hi Nav,

Glad that it is working now. Your understanding is correct. IPSEC transport mode encrypts the payload, while tunnel mode encrypts the whole ip packet (original header + payload) and inserts a new ip header. So, tunnel mode is used for site-to-site ipsec VPN, and transport is used for point-to-point ipsec VPN. When GRE is used with ipsec, all packets will be encapsulated with GRE header first, so essentially, that's a point-to-point ipsec VPN.

The problem you run into with tunnel mode is, on Router A, packet will be encapsulated with GRE header source from 192.168.248.253 destination to 217.155.113.179. The whole packet will then be encrypted and a new header is added with the same source/destination. This new header will be NATed by the FW, but the embedded/encrypted GRE header will not. When this packet get to Router B, after decrypt the packet, router B will see the GRE header which is different than tunnel source/destination that it uses. This breaks the GRE tunnel and routing protocol between router A and router B.

HTH,

Lei Tian

View solution in original post

6 REPLIES 6
Highlighted
Cisco Employee

Hi,

Can you share the configs on both ends?

HTH,

Lei Tian

Highlighted

Hi Lei , here are the 2 configs for the VPN routers. Hope it sheds some light.

Just to add i have removed the crypto map from the fa0/1 interfaces on both routers just so i can continue my work with the GRE tunnel.

Router A

version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname SERVER-RTR
!
boot-start-marker
boot-end-marker
!
logging buffered 4096
enable secret 5 $1$RihE$Po9HPkuvEHaspaD5ZC72m0
!
no aaa new-model
memory-size iomem 20
ip cef
!
!
!
!
no ip domain lookup
ip multicast-routing
!
multilink bundle-name authenticated
!
!
!
!
!
archive
log config
  hidekeys
!
!
crypto isakmp policy 1
authentication pre-share
crypto isakmp key XXXX address 217.155.113.179
!
!
crypto ipsec transform-set STRONG esp-aes
!
crypto map S2S_VPN 10 ipsec-isakmp
set peer 217.155.113.179
set transform-set STRONG
match address 101
!
!
!
controller E1 1/0
!
!
!
!
interface Tunnel0
bandwidth 100000
ip address 10.208.200.1 255.255.255.0
ip mtu 1400
ip pim dense-mode
ip route-cache flow
tunnel source FastEthernet0/1
tunnel destination 217.155.113.179
!
interface FastEthernet0/0
ip address 10.208.1.10 255.255.224.0
ip pim state-refresh origination-interval 30
ip pim dense-mode
ip route-cache flow
ip igmp version 1
duplex auto
speed auto
!
interface FastEthernet0/1
ip address 192.168.248.253 255.255.254.0
ip nbar protocol-discovery
ip route-cache flow
load-interval 60
duplex auto
speed auto
!
router eigrp 1
auto-summary
!
router ospf 1
log-adjacency-changes
network 10.208.0.0 0.0.31.255 area 0
network 10.208.200.0 0.0.0.255 area 0

!
ip forward-protocol nd
ip route 0.0.0.0 0.0.0.0 10.208.1.1
ip route 217.155.113.179 255.255.255.255 192.168.248.1
!
ip flow-export version 5
ip flow-export destination 192.168.249.198 9996
!
no ip http server
no ip http secure-server
!
access-list 101 permit gre host 192.168.248.253 host 217.155.113.179

ROuter B

version 12.4

service timestamps debug uptime

service timestamps log uptime

no service password-encryption

!

hostname BSU-RTR

!

boot-start-marker

boot-end-marker

!

enable secret 5 $1$VABE$6r6dayC90o52Gb8iZZgNP/

!

no aaa new-model

memory-size iomem 25

ip cef

!

!

!

!

no ip domain lookup

ip multicast-routing

!

multilink bundle-name authenticated

!

!

!

!

!

archive

log config

  hidekeys

!

!

crypto isakmp policy 1

authentication pre-share

crypto isakmp key XXXX address 37.205.62.5

!

!

crypto ipsec transform-set STRONG esp-aes

!

crypto map S2S_VPN 10 ipsec-isakmp

set peer 37.205.62.5

set transform-set STRONG

match address 101

!

!

!

controller E1 1/0

!

!

!

!

interface Tunnel0

bandwidth 20000

ip address 10.208.200.2 255.255.255.0

ip mtu 1400

ip pim dense-mode

tunnel source FastEthernet0/1

tunnel destination 37.205.62.5

!

interface FastEthernet0/0

ip address 10.208.102.1 255.255.255.0

ip helper-address 10.208.2.31

ip pim dense-mode

duplex auto

speed auto

!

interface FastEthernet0/1

ip address 217.155.113.179 255.255.255.248

ip nbar protocol-discovery

load-interval 60

duplex auto

speed auto

!

router ospf 1

log-adjacency-changes

network 10.208.102.0 0.0.0.255 area 0

network 10.208.200.0 0.0.0.255 area 0

!

ip forward-protocol nd

ip route 0.0.0.0 0.0.0.0 10.208.200.1

ip route 37.205.62.5 255.255.255.255 217.155.113.182

!

!

no ip http server

no ip http secure-server

ip pim bidir-enable

ip mroute 10.208.0.0 255.255.224.0 Tunnel0

!

access-list 101 permit gre host 217.155.113.179 host 37.205.62.5

Highlighted

Hi,

Let's add 'mode transport' under 'crypto ipsec transform-set' on both ends, and try.

HTH,

Lei Tian

Highlighted

Hi Lei

Thats great, it worked and the tunnel is up, but i have a question.

Why does it work in transport mode and not tunnel mode, and is their any security risk with running transport mode over the internet. I read somewhere that transport mode is usually used between two end points, which i guess is what i am doing here with the GRE.

2. when i run the command 'show ip nbar protocol discovery stats bit rate top n 10' i only get gre showing, when i was running it in tunnel mode (whilst both VPN routers where on public IPs) i was seeing ipsec showing.

Thanks

Nav

Highlighted

Hi Nav,

Glad that it is working now. Your understanding is correct. IPSEC transport mode encrypts the payload, while tunnel mode encrypts the whole ip packet (original header + payload) and inserts a new ip header. So, tunnel mode is used for site-to-site ipsec VPN, and transport is used for point-to-point ipsec VPN. When GRE is used with ipsec, all packets will be encapsulated with GRE header first, so essentially, that's a point-to-point ipsec VPN.

The problem you run into with tunnel mode is, on Router A, packet will be encapsulated with GRE header source from 192.168.248.253 destination to 217.155.113.179. The whole packet will then be encrypted and a new header is added with the same source/destination. This new header will be NATed by the FW, but the embedded/encrypted GRE header will not. When this packet get to Router B, after decrypt the packet, router B will see the GRE header which is different than tunnel source/destination that it uses. This breaks the GRE tunnel and routing protocol between router A and router B.

HTH,

Lei Tian

View solution in original post

Highlighted

Ahhh, easy....when you know why.

Thanks very much for your help and explanation.